THE PWTAG CONFERENCE heard about the Spa at St Sidwell’s Point, built to ultra-energy efficient standards with a special selection of materials that provide fantastic air quality, optimal temperatures and natural lighting.

The theme for the recent PWTAG annual conference was The Sustainable Pool and the opening presentations, in front of over 100 delegates, were right on the money. St Sidwell’s Point in Exeter is the world first leisure centre to be built to Passivhaus standards – in real terms, as economical in terms of energy use as technically possible.

Nic Bryant from architects Space & Place described how orientating the pool hall glazing south and dry areas’ north maximised solar gain and minimised overheating. Similarly, both heating and cooling air-source heat pumps were deployed.

St Sidwell’s Point is built to ultra-energy saving efficient Passivhaus standard. With a 70% on average annual energy and carbon saving potential, the building is a grand design and has been modelled to withstand predicted change in climate up to 2080.

Building biology is at the forefront of the design, and due to the selection of materials and design of the internal environment, customers can enjoy improved air quality, optimal air temperatures and natural lighting. Still on St Sidwell’s, Stephen Platt from Teal Consultancy spoke about its engineering challenges – from simple placement of screws in walls to brise soleil placed internally.

Testing and a high level of scrutiny, coupled with a holistic approach to energy and customer experience, were key. Finally on this theme, PWTAG’s Tom Devin and James Coombes, both from Devin Consulting, spoke about the principles and practice involved in Passivhaus. The first of those are set out in PWTAG’s online guidance note, Net zero carbon pools.

The practice included looking how hydraulic modelling assisted in the design of minimum headloss systems to minimise energy consumption. Sarah Dack, who represents The UK Health Security Agency on PWTAG, spoke about chlorate and the difficulty of determining what level can be considered safe in pool water.

PWTAG’s Susanne Surman Lee and Rachel Chalmers of the Cryptosporidium Reference Unit described the conflict between sustainability and microbiological safety – an issue that was then opened up for general discussion. After lunch attention focused on filtration as Andy Gee from Total Pool Chemicals and Lester Simmonds from Pool Sentry spoke about ceramic filtration (the method of choice at St Sidwell’s) and a study on the application of coagulants.

Ole Gronborg from Ultra Aqua in Denmark introduced two new pool technologies in the swimming pool industry – a gravity filter that reduced ammonia and filtration to reduce trichloramine levels in the atmosphere. The use of active oxygen to disinfect domestic hot tubs was described by Joanna Kite of Surespa.

Studies with Swansea university suggested that it dealt with E coli and Ps aeruginosa biofilms as well as chlorine-based products, at a range of temperatures and pH. The final presentation was a collaboration between Pool Sentry and Rachel Chalmers. They described a state-of-the-art mobile lab that is being used to measure the performance of polyaluminium chloride (PAC) coagulant, using turbidity and particle counts.

They should be able to assess the effect of different doses, evaluate the use of turbidity as a measure of filtration efficiency and indicate how far it is possible to predict water quality based on bathing load, circulation rate and filtration efficiency. A lively ‘Ask The Experts’ session closed another successful conference.

Pool Water Treatment Advisory Group